Update Directory.Packages.props

Author: SimonCropp

src/Directory.Packages.props

@@ -8,12 +8,12 @@
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="28.0.0-beta.10" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
     <PackageVersion Include="NUnit" Version="4.4.0" />
-    <PackageVersion Include="NUnit3TestAdapter" Version="6.0.1" />
+    <PackageVersion Include="NUnit3TestAdapter" Version="5.2.0" Pinned="true"/>
     <PackageVersion Include="Polyfill" Version="9.5.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.170" />
     <PackageVersion Include="Verify" Version="31.9.3" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.2" />
     <PackageVersion Include="Verify.Nunit" Version="31.9.3" />
     <PackageVersion Include="Microsoft.Sbom.Targets" Version="4.1.5" />
   </ItemGroup>
-</Project>
+</Project>